The present invention relates to a process for separation of hydrofluoric acid from is mixtures with 1,1,1-trifluoro-2,2-dichloroethane (HCFC 123) and/or 1,1,1,2-tetrafluoro-2-chloroethane (HCFC 124) and other halocarbon compounds, if any.
Various methods of separating and recovery HF from fluorocarbon composition are described in the art.
According to U.S. Pat. No. 3,406,099, the separation of CF.sub.3 COCF.sub.3, HF and CFCl.sub.2 CClF.sub.2 from their mixtures is carried out via azeotropic distillation.
U.S. Pat. No. 3,947,558 describes a process for separating HF from the fluorination products of chlorocarbons having 1-3 carbon atoms, which comprises the initial step of separating HCl, if any, then cooling the mixture in order to obtain two liquid phases, one rich in HF and the other poor in HF, and treating the latter with a glycol having 2-8 carbon atoms, so obtaining a glycolic phase rich in HF, which is then recovered by distillation.
According to U.S. Pat. No. 4,209,470, HF is separated from its liquid mixtures with 1-chloro-1,1-difluoroethane by addition of an auxiliary solvent selected from 1,1-dichloro-1-fluoroethane, vinylidene chloride and 1,1,1-trichloroethane with separation of a liquid phase impoverished in HF, from which HF is then separated by distillation.
Lastly, according to U.S. Pat. No. 4,944,846, the separation of HF from its mixtures with HCFC 123 and/or 124 is obtained by regulating the HF/HCFC 123 molar ratio in such mixture to values not exceeding 1.3, and then by subjecting said mixture to azeotropic distillation, thereby obtaining a head portion containing substantially all the HF and a part of HCFC 123 in the form of a HF/HCFC 123 azeotrope and, maybe, a HF/HCFC 124 azeotrope and a tail portion substantially free from HF, containing HCFC 123.